This invention relates generally to antennas for use in transmission of radio wave signals, and more particularly the invention relates to reflector antennas in which a reflector reflects signals from a feed to a selected target area.
In geosynchronous satellites, for example, a radio signal from a feed such as a conical or rectangular horn or dipole is directed to selected areas on earth by a suitable reflector positioned to receive and reflect the radio waves. The reflector surface is generally concave and is typically parabolic or deviated slightly from parabolic to provide required pattern illumination.
Coverage requirements can change for a satellite. Heretofore, this would require the provision of two separate antenna systems which can be selectively switched into operation as required. However, the provision of two antenna systems increases cost and weight. Moreover, the presence of two independent antenna systems creates problems of storage during satellite deployment.